Fix tessellator failure when a hole is touching another hole in the middle of a segment

lucene/CHANGES.txt

@@ -209,6 +209,9 @@ Bug Fixes
 
 * GITHUB#15702: Fix Potential NullPointException in BytesRefHash initialization#15702 (tyronecai)
 
+* GITHUB#15731: Fix tessellator failure when a hole is touching another hole in the middle of a segment. In this case
+  we might fail to detect it and choose a wrong bridge to eliminate the hole. (Ignacio Vera)
+
 Other
 ---------------------
 * GITHUB#15586: Document that scoring and ranking may change across major Lucene versions, and that applications requiring stable ranking should explicitly configure Similarity. (Parveen Saini)

lucene/core/src/java/org/apache/lucene/geo/Tessellator.java

@@ -392,7 +392,9 @@ private static Node eliminateHole(
       // compute if the bridge overlaps with a polygon edge.
       boolean fromPolygon =
           isPointInLine(bridge, bridge.next, holeNode)
-              || isPointInLine(holeNode, holeNode.next, bridge);
+              || isPointInLine(bridge, bridge.previous, holeNode)
+              || isPointInLine(holeNode, holeNode.next, bridge)
+              || isPointInLine(holeNode, holeNode.previous, bridge);
       // Split the resulting polygon.
       splitPolygon(bridge, holeNode, fromPolygon);
       return outerNode;
@@ -1260,8 +1262,8 @@ && area(a.getX(), a.getY(), a.previous.getX(), a.previous.getY(), b.getX(), b.ge
               >= 0;
     } else {
       // ccw
-      return area(a.getX(), a.getY(), b.getX(), b.getY(), a.previous.getX(), a.previous.getY()) < 0
-          || area(a.getX(), a.getY(), a.next.getX(), a.next.getY(), b.getX(), b.getY()) < 0;
+      return area(a.getX(), a.getY(), b.getX(), b.getY(), a.previous.getX(), a.previous.getY()) <= 0
+          || area(a.getX(), a.getY(), a.next.getX(), a.next.getY(), b.getX(), b.getY()) <= 0;
     }
   }
 

lucene/core/src/test/org/apache/lucene/geo/TestTessellator.java

@@ -938,13 +938,19 @@ public void testComplexPolygon61() throws Exception {
   public void testComplexPolygon62() throws Exception {
     String geoJson = GeoTestUtil.readShape("github-15657.geojson.gz");
     Polygon[] polygons = Polygon.fromGeoJSON(geoJson);
-    checkMultiPolygon(polygons, 1e-11);
+    checkMultiPolygon(polygons, 0.0);
   }
 
   public void testComplexPolygon63() throws Exception {
     String geoJson = GeoTestUtil.readShape("github-15695.geojson.gz");
     Polygon[] polygons = Polygon.fromGeoJSON(geoJson);
-    checkMultiPolygon(polygons, 1e-11);
+    checkMultiPolygon(polygons, 0.0);
+  }
+
+  public void testComplexPolygon64() throws Exception {
+    String geoJson = GeoTestUtil.readShape("github-15731.geojson.gz");
+    Polygon[] polygons = Polygon.fromGeoJSON(geoJson);
+    checkMultiPolygon(polygons, 0.0);
   }
 
   private static class TestCountingMonitor implements Tessellator.Monitor {